Eco-friendly and effectively glyphosate removal using novel banana peel-derived biopolymer-supported CoFeO activated peroxydisulfate: kinetic and mechanism insights.

In this work, an eco-friendly and novel heterogeneous catalyst deriving biopolymer extracted from banana peel for supporting CoFeO (CoFeO@BP-BiP) was successfully developed to activate peroxydisulfate (PDS) for mineralization removal of glyphosate (GP) herbicide from wastewater. GP mineralization performance, evaluating via COD removal efficiency, in CoFeO@BP-BiP/PDS system was compared with that in CoFeO/PDS system under various operational conditions. The chemical-physical properties were systematically analyzed to explore the mineralization mechanisms of GP. Quenching and competitive anion tests were conducted to study mineralization mechanisms of GP by CoFeO@BP-BiP activing PDS during catalytic process. The results illustrate that composition of BP-BiP and CoFeO remarkably reduced the agglomeration of nanoparticles and enriching oxygen-containing functional groups (OCFGs), which accelerated electron transfer cycles of Co/Co and Fe/Fe redox couples to continuously regenerate Fe and Co. This led to the effective decomposition of PDS, generating more reactive oxygen species (ROS) for promoted mineralization of GP. CoFeO@BP-BiP system exhibited higher GP mineralization performance and rate, approximately twofold greater than the CoFeO/PDS system. Mechanistic studies showed that GP mineralization occurred via both non-free radical and free radical pathways, involving ROS such as singlet oxygen (O₂) and radicals (SO, OH, O). Additionally, CoFeO@BP-BiP demonstrated excellent stability and reusability across five consecutive runs with minimal Co and Fe leaching. These findings suggest that CoFeO@BP-BiP is an effective and sustainable catalyst for activating PDS in the removal of glyphosate from wastewater.